“Applicability. This regulation applies to t h e A c t i v e A r m y , t h e A r m y N a t i o n a l
Guard/Army National Guard of the United States, and the U.S. Army Reserve, unless
otherwise stated.”

As to AROTC cadets status, do a search on this forum for thread: Are Army ROTC Cadets in the Army?

And as to UCMJ being applicable to AROTC cadets:
“Cadets and midshipmen at the United States Military Academy, United States Naval Academy, United States Air Force Academy, United States Merchant Marine Academy, and United States Coast Guard Academy are also subject to the UCMJ. On the other hand, Reserve Officers’ Training Corps (ROTC) cadets and midshipmen are by law exempt from the UCMJ (even while on active duty for training such as CTLT, LTC, LDAC, or while attending various training schools such as Airborne School, Air Assault School, Mountain Warfare School, etc.).”

Seems logical that if a cadet violates some provision of AR600-20, then while they may not be court martialed, could still be booted from AROTC; lower standard of review.